Highly purified metal material and sputtering target using the same

Abstract

This is a highly purified metal comprising one metal selected from the group consisted of titanium, zirconium and hafnium. The highly purified metal has an Al content of not more than 10 ppm. It also has an oxygen content of more than 250 ppm, each of Fe, Ni and Cr contents not more than 10 ppm and each of Na and K contents not more than 0.1 ppm. The highly purified metal is obtained by either purifying crude metal by the iodide process or surface treating crude metal to remove a contaminated layer existing on the surface thereof and then melting The surface treated material with electron bean in a high vacuum.

What is claim is: 
     
       1. A method of producing a wiring network on a substrate of a semi-conductor device, comprising the steps of: forming a thin film on said substrate of the semi-conductor device by sputtering a target consisting essentially of a highly purified metal comprising a metal selected from the group consisting of titanium, zirconium and hafnium, each containing not more than 10 ppm of Al; and   treating said thin film by etching to remove portions other than the desired wiring network.   
     
     
       2. The method of producing the wiring network according to claim 1, wherein said thin film comprises a nitride of one of said metals. 
     
     
       3. A method of producing a wiring network according to claim 2, wherein said metal is titanium. 
     
     
       4. A method of producing a wiring network according to claim 2, wherein said metal is zirconium. 
     
     
       5. A method of producing a wiring network according to claim 2, wherein said metal is hafnium. 
     
     
       6. The method of producing the wiring network according to claim 1, wherein said semiconductor contains silicon, and said method further comprises the step of forming a silicide film from said thin film. 
     
     
       7. A method for producing a wiring network according to claim 6, wherein the step of forming the silicide film comprises a two step annealing treatment. 
     
     
       8. A method of producing a wiring network according to claim 7, wherein said metal is titanium. 
     
     
       9. A method of producing a wiring network according to claim 7, wherein said metal is zirconium. 
     
     
       10. A method of producing a wiring network according to claim 7, wherein said metal is hafnium. 
     
     
       11. A method of producing a wiring network according to claim 6, wherein the step of forming the silicide film takes place after said treating step. 
     
     
       12. A method of producing a wiring network according to claim 6, wherein said metal is titanium. 
     
     
       13. A method of producing a wiring network according to claim 6, wherein said metal is zirconium. 
     
     
       14. A method of producing a wiring network according to claim 6, wherein said metal is hafnium. 
     
     
       15. The method of producing the wiring network according to claim 1, wherein said highly purified metal contains not more than 250 ppm of oxygen; not more than 10 ppm each of elements consisting of Fe, Ni and Cr, and not more than 0.1 ppm each of elements consisting of Na and K. 
     
     
       16. A method of producing a wiring network according to claim 15, wherein said metal is titanium. 
     
     
       17. A method of producing a wiring network according to claim 15, wherein said metal is zirconium. 
     
     
       18. A method of producing a wiring network according to claim 15, wherein said metal is hafnium. 
     
     
       19. A method of producing a wiring network according to claim 1, wherein said metal is titanium. 
     
     
       20. A method of producing a wiring network according to claim 1, wherein said metal is zirconium. 
     
     
       21. A method of producing a wiring network according to claim 1, wherein said metal is hafnium. 
     
     
       22. A method of producing a wiring network according to claim 13, wherein said highly purified metal is produced by a method comprising the steps of: purifying a crude metal by an iodide process, and   melting said purified metal with an electron beam in a high vacuum.   
     
     
       23. A method of producing a wiring network according to claim 1, wherein said highly purified metal is produced by a method comprising the steps of: purifying a crude metal by a fused salt electrolysis process,   subjecting said metal to a surface treatment to remove a contaminated layer existing on the surface of said crude metal, and   melting said purified metal with an electron beam in a high vacuum.